Re: Porting gdb to Cyclops64

[Brian Heilig <bheilig@etinternational.com>]

Guys, thanks again for all your help. My target is reporting events in a
sane order in stop mode now but I've run into a snag.

While debugging the following program:

#include <stdio.h>                      /* line 1  */
void foo(int *a) {                      /* line 2  */
  *a = 9;                               /* line 3  */
}                                       /* line 4  */
int main() {                            /* line 5  */
  int a=0;                              /* line 6  */
  foo(&a);                              /* line 7  */
  printf("%d\n",a);                     /* line 8  */
  return 0;                             /* line 9  */
}

I set a breakpoint at line 7. All threads hit that breakpoint. I stepped
thread 1 and continued the other threads.

[Switching to Thread 1]

Breakpoint 1, main () at step.c:7
7	  foo(&a);                              /* line 7  */
(gdb) s
[Switching to Thread 2]

Breakpoint 1, main () at step.c:7
7	  foo(&a);                              /* line 7  */
(gdb) c
Continuing.
[Switching to Thread 3]

... etc.

(gdb) c
Continuing.

Program received signal SIGTRAP, Trace/breakpoint trap.
[Switching to Thread 1]
0x0000000080800274 in main () at step.c:7
7	  foo(&a);                              /* line 7  */

I switched back to thread 1 and step again:

(gdb) s
foo (a=0x41103ae8) at step.c:3
3	  *a = 9;                               /* line 3  */
(gdb) 

I step one more time and gdb switches to thread 2. Why is that?

(gdb) s

Program received signal SIGTRAP, Trace/breakpoint trap.
[Switching to Thread 2]
foo (a=0x41803ae8) at step.c:3
3	  *a = 9;                               /* line 3  */

It turns out that when I stepped to line 3 (the second step) gdb
actually set a breakpoint at line 3. This might be because 'foo' has
been inlined. Then gdb told my target to continue all "vCont;c". All
threads hit the breakpoint, but only thread 1 should have.

I don't know how it's supposed to work, but gdb could have sent
"vCont;c:1". Or gdb could have single stepped until it reached the
correct address (obviously not the preferred method). How can I correct
this?

Thanks,
Brian